You need a cat. Get a good quality cat not a cheap one. After it is repaired, it needs to be driven to see if the missfire goes away. The 101 is a mass air flow code but doesn not mean it needs to be replaced. Have it checked first
August, 28, 2013 AT 4:10 PM
Which cat would this be referring to? There's one connected to the exhaust manifold itself on the 2.4l and then there is either another one before the muffler or a resonator. Only saw sensors near the first one.